Electrical discharge tube



Oct. 20, 1959 c. F. MILLER ELECTRICAL DISCHARGE TUBE 2 Sheets-Sheet 1 Filed Feb. 26. 1953 INVENTOR' Carl F. Miller.

WITNEISSES: xftw ATTORNEY ELECTRICAL DISCHARGE TUBE Filed Feb. 26, 1953 2 Sheets-Sheet 2 WITNESSES: INVENTOR Carl F. Miller.

[ATTORNEY United States Patent Ofiice 2,909,700 Patented Oct. 20, 1959 ELECTRICAL DISCHARGE TUBE Carl F. Miller, Bath, N.Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 26, 1953, Serial No. 339,036

7 Claims. (Cl. 313257) My invention relates to electrical discharge tubes and relates in particular to electrode structures especially adapted to tubes subject to vibration or shock, and also to tubes operating in ambient temperatures of extreme values. An important advantage of such electrode structures is the minimization of drift and expansion during the warm-up period and general absence of distortion due to temperature change.

One object of my invention is accordingly the production of a new and improved electrical discharge device.

Another object is the production of an electrical discharge tube which is rugged and well able to operate where subject to shockor vibration.

Another object is the production of an electrical discharge tube able to operate satisfactorily over a wide range of ambient temperatures.

Still another object is the production of an electrical discharge tube which shows little variation of its electrical characteristics when subject to temperature change, due either to warming up when started in operation or to other causes.

Yet another object is the provision of a tube well adapted to mass production and of moderate cost.

Other objects of my invention will become apparent upon reading the following description taken in connection with the drawings, in which:

Figure 1 is a perspective view partly broken'away, of an electrical discharge tube embodying the principles'of my invention;

Fig. 2 is a sectional View along the line IIII in Fig. 3, and Fig. 3 a sectional elevation of the electrode struc ture of Fig. 1; and

Figs. 4, 5 and 6 are views in transverse section of forms of the electrode structure.

Referring in detail to the drawings a vacuum-tight container 1 which may be of glass has a base 2 through which are sealed in conventional fashion in-leads for an anode, cathode with heater, and those grids forming a pentode. These electrodes are supported as appears more clearly in Figs. 2 and 3 on a cylinder 3- which may be of ceramic material or may be of metal. The inner face of cylinder 3 is provided with undercut grooves in which are seated a plurality of ceramic members 4, roughly wedge-shaped which radiate from a cathode cylinder 5 the axis of the cylinder 3. Each member 4 is held in position by a through-bolt 6 having springs at each end which bias a pair of ceramic end plates 7 against the ends of members 4. The cathode 5 may be of conventional unipotential type comprising a sleeve member containing a heater. The sleeve member of the cathode 5 is provided with an electron emissive coating extending between the end plates 7. The side walls of the ceramic members 4 are of stepped form in the Figs. 2-3 modification and the separate steps are metallized and constitute the control-grid 8, screen grid 9, and suppressor grid 11. If the cylinder 3 is of metal, its inner face acts as the anode; if it is of ceramic, the inner face is metallized on the portions lying between the members 4 Circuit connections to the grids'8, 9 and 11 are by three contact rings 12, 13, 14 which are held in contact with the lower ends of the grids by the pressure of the springs acting on end-plates 7. The contact rings are provided with dotwnturne'd ends which are connected to in-leads 15, 16, 17 sealed through the base 2 of container 1. The terminals of the heater for cathode 5 are connected to in-leads 18. An in-lead 21 is connected directly to cathode 5. A getter with tab 22 is supported on a post set in the upper end-plate near the exhaust-tip 23 The electrode structure is assembled first as a unit; then aligned with the in-leads in base 2 and Welded thereto. The bulb 1 may then be fused in place to base 2 in a conventional tube machine.

In Fig. 4 the ceramic members 4 of Fig. 2 are replaced by hollow ceramic pieces 31 having thin vanes or walls which project radially toward the central axis of the metal anode cylinder 3. Each of the vanes has three metallized stripes 33, 34, 35 at different radial distances and parallel to the axis of cylinder 3 which function respectively as control grids, screen grids and suppressor grids. The stripes 33 are all interconnected by a ring similar to ring 12 in Fig. 2; the stripes 34 by a ring similar to ring13 on Fig. 2; and the stripes 35 by a ring similar to ring 14 in Fig. 2. The inner face of each ceramic 31 is provided with a metallized stripe 36, the latter being interconnected by a metal ring similar to rings 12, 13, 14, which are connected to the anode in-lead 37 through tube-base 2. Otherwise the arrangements of tubes employing ceramics of the Fig. 4 type are like those of Fig. 2.

Fig. 5 shows still another form of wedge-shaped ceramic in which solid ceramic wedges are provided with three stepped faces at different radial distances from the cathode 5. The three sets of stepped faces are metallized to provide a control grid, screen grid and suppressor grid respectively. In the Fig. 5 species, the stepped faces of a ceramic are all parallel to the radial central plane of the ceramic. Otherwise the structure and mode of connections for the 'Fig. 5 species are like those of the Fig. 2 species.

In Fig. 6 the ceramics have only two steps which have faces parallel to the axial plane which is midway between two adjacent ceramics. However, the radially inward step has two metallized stripes 33, 34- at different radial distances which constitute the control-grid and the screen-grid. The radially outer step 35 is metallized to provide the suppressor grid. The connections to the grids are similar to those of Fig. 2. The metal supporting cylinder 3 in which the ceramics are seated is the anode.

I claim as my invention:

1. An electrical discharge tube comprising; a vacuum type container enclosing an electrode structure comprising a cylindrical wall having conducting anode areas on its inner surface, a cathode comprising a cylindrical member having an electron emissive coating thereon, said cathode position coaxially with respect to said wall, a plurality of individual fingers of insulating material fixed to said wall and projecting radially inward toward said cathode, conductors parallel to the axis of said cathode and of substantially the same length as said electron emissive coating, said conductors afiixed to the walls of said fingers, said anode areas being disposed on said inner surface between adjacent fingers and connections from said anode areas, said cathode and said conductors to in-leads through the wall of said container.

2. An electrical discharge tube comprising a vacuum type container enclosing an electrode structure said electrode structure comprising a metallic cylindrical wall, an electron emissive member positioned in an axial region of said cylindrical wall, a plurality of individual fingers of ceramic material having their radially outward ends set in said cylindrical wall, said ends being physically separated from each other by conductive portions of said wall, said fingers extending radially inward toward said electron emissive member, conductors on the side walls of said fingers and of substantially the same length as said electron emissive member and parallel to T the axis of said electron emissive member, and connections from said cylinder, said conductors and said electron emissive member sealed through the walls of said container.

3. An electrical discharge device comprising a vacuum type container comprising a tubular support wall having conductive anode areas positioned on the inner surface, an electron emissive member centrally located within said tubular wall, a plurality of individual fingers of insulating material projecting radially inward towards said electron emissive member, said anode areas disposed on the inner surface between adjacent fingers, and conductive strip electrode areas positioned on said fingers parallel to the axis of said electron emissive coating and of substantially the same length as said electron emissive member.

4. An electrical discharge device comprising a vacuum container and having therein a tubular support wall having conducting anode areas positioned on the inner surface, an electron emissive electrode centrally located Within said wall, a plurality of individual fingers of insulating material projecting radially inward towards said electron emissive electrode, a conductive grid electrode area positioned on each of said fingers equal distance from said electron emissive electrode, said grid electrode areas being parallel to the axis of said electron emissive electrode and of substantially the same length as said electron emissive electrode and means to connect said grid electrode areas to provide a grid structure intermediate said electron emissive electrode and said anode.

5. An electrical discharge device comprising; a vacuum type enclosure having therein a tubular support wall having conductive anode areas disposed on the inner surface, an elongated electron emissive electrode coaxially positioned within said tubular wall, a plurality of individual fingers of insulating material projecting radially inward toward said electron emissive electrode, a plurality of conductive grid electrode areas disposed on said fingers at predetermined distances from said electron emissive electrode, said grid electrode areas being parallel to the axis of said electron emissive electrode and of substantially the same length as said electron emissive electrode and conductive means connecting those grid areas equal distance from said cathode to form a plurality of spaced grid members between said electron emissive electrode and said anode.

6. An electrical discharge tube comprising; a vacuum type container enclosing an electrode structure comprising a cylindrical wall having conducting anode areas on its inner surface, a cathode comprising a cylindrical member and having an electron emissive coating thereon, said cathode cylinder positioned coaxially with respect to said cylindrical wall, a plurality of individual fingers of insulating material fixed to said wall and projecting radially inward toward said cathode, conductors in the form of metallized strips provided on the surface of said ceramic fingers parallel to the axis of said cathode cylinder and of substantially the same length as said electron emissive coating, said anode areas being disposed on said inner surface between adjacent fingers in connections from said anode areas, said cathode and said conductors to in-leads through the wall of said container.

7. An electrical discharge tube comprising a vacuum type container enclosing an electrode structure comprising a metallic cylindrical wall, an electron emissive member positioned in the axial region of said cylindrical wall, a plurality of individual fingers of ceramic material having their radially outward ends set in said cylindrical wall, said ends being physically separated from each other by conductive portions of said wall, said fingers extending radially inward toward said electron emissive member, conductors on the side walls of said fingers and of substantially the same length as said cathode and parallel to the axis of said electron emissive member, said side walls having stepped portions carrying said conductors and being parallel to the axial plane midway between adjacent fingers.

References Cited in the file of this patent UNITED STATES PATENTS 2,002,667 Knoll May 28, 1935 2,012,038 Eitel et al. Aug. 20, 1935 2,084,867 Prinz et al. June 22, 1937 2,098,380 Engelmann et al. Nov. 9, 1937 2,201,216 Baier et al. May 21, 1940 FOREIGN PATENTS 502,101 Great Britain Mar. 10, 1939 

